The mission included co-operation from 14 other nations including Sweden, Switzerland, Austria, France, West Germany, and the United States (who contributed the use of its Deep Space Network for tracking the twin spacecraft). The objectives of the dual mission were to 1) conduct studies of the interplanetary environment, 2) perform observations of the Sun, 3) characterize the plasma environment in the Martian vicinity, 4) conduct surface and atmospheric studies of Mars, and 5) study the surface composition of the Martian satellite Phobos.

In support of these objectives, the mission was to perform the first close scientific investigation of and landing on another planet's moon. In addition to their on-board instrument complement, each vehicle carried a lander designed to land on Phobos' surface and perform a number of in-situ measurements. Phobos 2 also carried a second, smaller "hopper" lander designed to land on Phobos and then use its spring loaded legs to move ("hop") about the moon's surface to make chemical, magnetic and gravity observations at different locations. Phobos 2 operated nominally throughout its cruise and Mars orbital insertion phases, gathering data on the Sun, interplanetary medium, Mars, and Phobos. Phobos 2 entered Mars orbit on January 29, 1989. Contact with the vehicle was lost on March 27, 1989 shortly before the final phase of the mission during which the spacecraft was to approach within 50 meters of Phobos' surface and release its two landers. The cause of the failure was determined to be a malfunction of the on-board computer.

The main section of the spacecraft consisted of a pressurized toroidal electronics section surrounding a modular cylindrical experiment section. Below these were mounted four spherical tanks containing hydrazine for attitude control and, after the main propulsion module was to be jettisoned, orbit adjustment. A total of 28 thrusters (twenty-four 50 N thrusters and four 10 N thrusters) were mounted on the spherical tanks with additional thrusters mounted on the spacecraft body and solar panels. Attitude was maintained through the use of a three-axis control system with pointing maintained with sun and star sensors. Power was generated via solar arrays. The Mars orbit insertion maneuver was performed by a dedicated propulsion module utilizing used nitric acid and an amine-based fuel, with a 9.86-18.89 kN variable thrust chamber and eight helium pressurized aluminum alloy tanks. After achieving the final orbit, the orbit insertion module was jettisoned, exposing the downward viewing instruments on the main structure. Mass was 2600 Kg in Martian orbit (6220 Kg with orbital insertion hardware attached). The computer had 30 Mbit memory storage. Downlink was via a 2 degree-of-freedom parabolic high gain antenna at 4 kbits/sec. The larger Phobos landers would have transmitted data directly to Earth at 4-20 bits/sec on 1.672 Ghz to 70 m Soviet dishes. 'Hopper' lander data would have been relayed via the orbiter.

The payload included a TV imaging system, a thermal infrared spectrometer/radiometer with 1-2 km resolution; a near-infrared imaging spectrometer; a thermal imaging camera; magnetometers; gamma-ray spectrometers; an X-ray telescope; radiation detectors; and radar and laser altimeters. The 'Hopper' lander was designed to make chemical, magnetic and gravity observations at different locations on Phobos' surface. Only carried by Phobos 1 was the Lima-D laser experiment, designed to vaporize material from the Phobos surface for chemical analysis by a mass spectrometer, and an imaging radar. Only carried by Phobos 2 was the 'DAS' platform lander, which carried a panoramic stereo TV system, seismometer, magnetometer, X-ray fluorescence spectrometer, alpha particle scattering device, and penetrator.

Proton The Proton launch vehicle has been the medium-lift workhorse of the Soviet and Russian space programs for over forty years. Although constantly criticized within Russia for its use of toxic and ecologically-damaging storable liquid propellants, it has out-lasted all challengers, and no replacement is in sight. More...

Associated Launch Vehicles

Proton The Proton launch vehicle has been the medium-lift workhorse of the Soviet and Russian space programs for over forty years. Although constantly criticized within Russia for its use of toxic and ecologically-damaging storable liquid propellants, it has out-lasted all challengers, and no replacement is in sight. Development of the Proton began in 1962 as a two-stage vehicle that could be used to launch large military payloads or act as a ballistic missile with a 100 megaton nuclear warhead. The ICBM was cancelled in 1965, but development of a three-stage version for the crash program to send a Soviet man around the moon began in 1964. The hurried development caused severe reliability problems in early production. But these were eventually solved, and from the 1970's the Proton was used to launch all Russian space stations, medium- and geosynchronous orbit satellites, and lunar and planetary probes. More...

Proton-K/D-2 Russian orbital launch vehicle. This four stage version of the Proton was a modification of the original Block D / 11S824M for launch of late 1980's Lavochkin OKB probes on missions to Mars. Guidance to the Block D-2 stage must be supplied by spacecraft. More...

National Space Science Center Planetary Page, As of 19 February 1999.. Web Address when accessed: here.

Associated Launch Sites

Baikonur Russia's largest cosmodrome, the only one used for manned launches and with facilities for the larger Proton, N1, and Energia launch vehicles. The spaceport ended up on foreign soil after the break-up of Soviet Union. The official designations NIIP-5 and GIK-5 are used in official Soviet histories. It was also universally referred to as Tyuratam by both Soviet military staff and engineers, and the US intelligence agencies. Since the dissolution of the Soviet Union the Russian Federation has insisted on continued use of the old Soviet 'public' name of Baikonur. In its Kazakh (Kazak) version this is rendered Baykonur. More...

Contact lost with Phobos 2 probe - .
Nation: USSR. Spacecraft: Fobos 1F. Phobos 2 operated nominally throughout its cruise and entered Mars orbit on January 29, 1989. Contact with the vehicle was lost on March 27, 1989 shortly before the final phase of the mission during which the spacecraft was to approach within 50 meters of Phobos' surface and release its two landers. The cause of the failure was determined to be a malfunction of the on-board computer.